The present invention relates generally to the sprinkler art, and, more particularly to a condensate drain for a dry pipe sprinkler system.
Automatic sprinkler systems include piping and devices to detect when a fire is occurring and automatically actuating to dispense water on the area where the fire is occurring sprinkler systems are basically made of the following components: a public water supply or a private water supply to supply water to the main riser; a main sprinkler riser equipped with control valves and alarm devices; the main sprinkler riser feeds water to sprinkler bulk mains that carry water throughout the building to sprinkler heads.
Sprinkler bulk mains, smaller cross-mains, and branch lines make up the piping network to supply individual sprinkler heads.
Thermally actuated water spray sprinkler heads are located throughout the area to be protected and are connected to the piping branch lines. In heated buildings the piping system is full of water under pressure and is ready to apply water to a fire whenever a sprinkler head opens.
In unheated buildings a special control valve (a dry-pipe valve) is installed in the sprinkler main riser. The dry-pipe valve keeps the piping system dry by holding back the water until a sprinkler head opens. The dry side of the control valve is filled with pressurized air.
In dry-pipe systems, when a sprinkler head opens, the air escapes faster than it can be replenished and the dry-pipe valve opens, filling the piping system with water and dispenses water on the fire.
Dry-pipe systems tend to collect condensate inside the piping system that must be periodically drained. If the condensate is not drained, freezing temperatures will cause ice to form in the piping system, causing the pipe and pipe fittings to burst.
In order to deal with this problem several solutions have been proposed.
U.S. Pat. No. 6,102,066 discloses a condensate drain for an automatic sprinkler system of the dry-pipe type in which there is an arrangement for periodic manual operation of valves to remove condensate. This system has a condensate reservoir with a valve at each end.
It is an object of the present invention to provide for removal of condensate from dry pipe sprinkler systems.
It is another object of the present invention to provide for the discharge of such condensate automatically.
These objects and others are accomplished in accordance with preferred embodiments of the present invention. For example, a pressure operated normally closed control valve operates to open at a predetermined pressure between the system minimum and maximum pressures to open the valve and allow the discharge of condensate from the system which has a source of pressure to provide a minimum and a maximum pressure. The system is subject to the formation of condensate. There is an inline filter at the inlet end of the valve and a discharge nozzle at the outlet end of the valve. The entrance to the discharge nozzle may also have a filter. The assembly can also be arranged so that the control valve is normally open and operates to open at a predetermined pressure at or below the system minimum pressure whereby condensate is removed, and to close the valve and prevent the discharge of condensate from the system when the pressure falls below the predetermined pressure.